--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -2121,17 +2121,17 @@ nsPresContext::MediaFeatureValuesChanged
     // Copy pointers to all the lists into a new array, in case one of our
     // notifications modifies the list.
     nsTArray<RefPtr<mozilla::dom::MediaQueryList>> localMediaQueryLists;
     for (auto* mql : mDocument->MediaQueryLists()) {
       localMediaQueryLists.AppendElement(mql);
     }
 
     // Now iterate our local array of the lists.
-    for (auto mql : localMediaQueryLists) {
+    for (const auto& mql : localMediaQueryLists) {
       nsAutoMicroTask mt;
       mql->MaybeNotify();
     }
   }
 }
 
 void
 nsPresContext::PostMediaFeatureValuesChangedEvent()